Avermectin compounds are known antiparasitic agents of considerable activity. The basic material products are described in U.S. Pat. No. 4,310,519. The 22,23-dihydro derivatives are disclosed in U.S. Pat. No. 4,199,569. The monosaccharide and aglycone derivatives are disclosed in U.S. Pat. No. 4,206,205. The 13-deoxy avermectin compounds are disclosed in Re 32034 and Re 32006. The instant hydroxy adducts are significantly different from such compounds.